Slight Judder with VDPAU
#1
My XBMC setup is at about 90% satisfaction for me, there is only ONE issue I have not been able to eliminate: an occasional frame skip with vdpau activated. If I can correct this issue I can seriously consider selling my blu-ray player!

Hardware: Athlon X2 5000+
Geforce 240 GT

Software: Ubuntu 10.04 LTS
Nvidia Drivers 260.19.29
XBMC 10.0 (not live)

So, when watching any source with vdpau enabled, 480p/720p/1080p, every so often, there will be a slight frame skip, it is hardly noticeably, but I do notice it, and it is really distracting. It is non-repeatable, that is to say, random. It does not matter if the bit-rate is really high or low. When it happens, if I jump back, it will not repeat.

I have tried enable/disable sync. It seems slightly better with sync disabled, but the problem persists. It is not a dropped frame, as when it happens, the dropped frame counter remains the same. I tend to drop no more than 10-25 frames per movie. Playback is extremely solid except for this issue.

Now, here is the odd part, if I disable vdpau, the issue goes away. All play back is flawless. The downside, my system is not powerful enough to play hi motion 1080p material without a shutter. Dropped frames rise into the 100s.

I did run a log, the only thing of note is there are some consume packet errors in the log. Other than that is looks fine. I have not check to see if this is in the log without vdpau.

I have seen other threads that speak of vdpau judder, but the posted issues seem much worse then what I am experiencing. This is like one frame, every 1-3 mins.

Any ideas?
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#2
Hi there

my first question is are you streaming from a NAS or storage PC or are these local files.

If its a NAS are you connected via an SMB (Samba) share or an NFS mount.

I noticed most of my issues with 9.11 (waiting for the PPA to be sorted out for 10 under karmic) went away or became less noticable when I moved from SMB shres to NFS mounts.
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#3
Good question.

Files are stored locally. I am pretty sure it is not a throughput/bus issue as the problem goes away if vdpau is turned off. Plus the issue is no greater for 1080p vice 480p.

I am about 98% sure it is vdpau. The question is, how do I fix it!

I am thinking of rolling back to an earlier driver, but I would like to hear from more if this issue has always existed.

Thanks.
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#4
Use you using refresh rate matching?

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#5
Affejunge Wrote:My XBMC setup is at about 90% satisfaction for me, there is only ONE issue I have not been able to eliminate: an occasional frame skip with vdpau activated. If I can correct this issue I can seriously consider selling my blu-ray player!

Hardware: Athlon X2 5000+
Geforce 240 GT

Software: Ubuntu 10.04 LTS
Nvidia Drivers 260.19.29
XBMC 10.0 (not live)

So, when watching any source with vdpau enabled, 480p/720p/1080p, every so often, there will be a slight frame skip, it is hardly noticeably, but I do notice it, and it is really distracting. It is non-repeatable, that is to say, random. It does not matter if the bit-rate is really high or low. When it happens, if I jump back, it will not repeat.

I have tried enable/disable sync. It seems slightly better with sync disabled, but the problem persists. It is not a dropped frame, as when it happens, the dropped frame counter remains the same. I tend to drop no more than 10-25 frames per movie. Playback is extremely solid except for this issue.

Now, here is the odd part, if I disable vdpau, the issue goes away. All play back is flawless. The downside, my system is not powerful enough to play hi motion 1080p material without a shutter. Dropped frames rise into the 100s.

I did run a log, the only thing of note is there are some consume packet errors in the log. Other than that is looks fine. I have not check to see if this is in the log without vdpau.

I have seen other threads that speak of vdpau judder, but the posted issues seem much worse then what I am experiencing. This is like one frame, every 1-3 mins.

Any ideas?

Yeah I have one, is your TV capable of performing a full pulldown? You will get judder no matter what if your tv is using a 3:2 pulldown while you're watching 24p content (bluray).

Same goes if you're in 60hz and you're watching movies that are encoded in 24fps, 24 - 60 (3:2 pulldown)


I think I know what you're talking about, it seems like for a split second or so, the action on your scree goes into some sort of slow-motion right?

I'm running a 120hz tv with proper 24p but xbmc still gives me random slow-motion skips with vdpau on or off.


120hz/24 = 5 5:5
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#6
poofyhairguy Wrote:Use you using refresh rate matching?

Yup. Funny you mention that, I was thinking of seeing what happens with it off.
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#7
greenfish Wrote:Yeah I have one, is your TV capable of performing a full pulldown? You will get judder no matter what if your tv is using a 3:2 pulldown while you're watching 24p content (bluray).

My TV supports 24fps natively and I am rate matching my output. Again, since it goes away with vdpau turned off, I believe it is something inherent in VDPAU.

I would leave vdpau off if my video card was fast enough to handle 1080p w/o vdpau. The vcpu is like at 93% watching calm 1080p video with each core at 80%. If there is any jump in bitrate...watch dem frames drop! Smile

My kids are home from school now, which means I have lost access to test till this evening. I have a few BIOS tweaks I am going to try.
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#8
Affejunge Wrote:My TV supports 24fps natively and I am rate matching my output. Again, since it goes away with vdpau turned off, I believe it is something inherent in VDPAU.

Judder is something that pops up when you DO have 24p working correctly:

http://www.projectorcentral.com/judder_24p.htm

That is making me think that with VDPAU it is no longer doing pulldown, and therefore you are seeing judder that exists naturally in the source. Sometimes pulldown can look WAY smoother than 24p...

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#9
Hi, I don't know what is VDPAU but I'm using apple tv with crystal hd with a pioneer KRP 600 that have 24p nativity. I'm using bluray rip and 24p output. All is very smooth but random i have a frame drop (like slowmotion). THis happen 5-6 times for movie....
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#10
poofyhairguy Wrote:Judder is something that pops up when you DO have 24p working correctly:

http://www.projectorcentral.com/judder_24p.htm

That is making me think that with VDPAU it is no longer doing pulldown, and therefore you are seeing judder that exists naturally in the source. Sometimes pulldown can look WAY smoother than 24p...

Thanks for the link, very informative. But, the "judder" they are talking about, from filming at 24fps (which in part why video looks smooth and 120hz looks freaky) should be repeatable as the play the scene over and over (as referenced in the article).

What I am experience is not repeatable. If it happens, and I skip back, it will not repeat in the same place. Maybe "judder" is the wrong word, it is more like a single frame skip. If I am in "sync mode", the error counter will go up by 1 when it happens, but dropped frames does not increase. So, it something to do with sync. It is there whether or not am using "sync". The only way I can make it go away is without using VDPAU.

But the question remains..why is it gone with VDPAU disabled?
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#11
I know exactly what you mean as I have seen it on my Linux box, but I want to say that I ALSO see it on my Mac Mini running the XBMC port for OSX natively as well. I used to run Ubuntu on that box but went native when OSX to acceleration (though I believe it only worked on the Nvidia card Mac Minis as well, so this may be the same VDPAU acceleration).

But I can agree I see it and it is very frustrating. Never does it at the same spot if you rewind, very noticeable, as if frames are getting dropped and things suddenly slow down for 2-3 seconds, but I don't believe when I pop up the GUI it actually reports that it dropped frames.

I do use SMB shares and it happens when streaming mkv content of 720p or 1080p, I don't watch a lot of SD content so it's tough to say if it does it with SD as well. Interesting thing to see above someone suggested it might be SMB causing the issue, first I ever saw that mentioned before.
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#12
BDPNA Wrote:I know exactly what you mean as I have seen it on my Linux box, but I want to say that I ALSO see it on my Mac Mini running the XBMC port for OSX natively as well. I used to run Ubuntu on that box but went native when OSX to acceleration (though I believe it only worked on the Nvidia card Mac Minis as well, so this may be the same VDPAU acceleration).

But I can agree I see it and it is very frustrating. Never does it at the same spot if you rewind, very noticeable, as if frames are getting dropped and things suddenly slow down for 2-3 seconds, but I don't believe when I pop up the GUI it actually reports that it dropped frames.

I do use SMB shares and it happens when streaming mkv content of 720p or 1080p, I don't watch a lot of SD content so it's tough to say if it does it with SD as well. Interesting thing to see above someone suggested it might be SMB causing the issue, first I ever saw that mentioned before.

I have the EXACT same thing. Everytime I watch an HD movie (all 1080p) certain scenes goes into a slowmo for a split second or so, and rewinding doesn't fabricate the error.

Update: Watched braveheart 1080p (24p - x264 4.1) I counted at least 5-8 scenes where this "slowmo" occurred. Checking the output log shows 50 frames dropped in the entire movie, about 2 hours.

SMB isn't the issue, all of my content is all local or streamed from a sever with smb. Braveheart was all local.

I also have 1GB switches just in case.
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#13
Seeing the same here. Running from a 9.11 bootdisc everything ran fine, might be worth a check for you as well. Some of my scenes are reproduceable though, always in the same parts.
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#14
greenfish Wrote:I have the EXACT same thing. Everytime I watch an HD movie (all 1080p) certain scenes goes into a slowmo for a split second or so, and rewinding doesn't fabricate the error.

Update: Watched braveheart 1080p (24p - x264 4.1) I counted at least 5-8 scenes where this "slowmo" occurred. Checking the output log shows 50 frames dropped in the entire movie, about 2 hours.

SMB isn't the issue, all of my content is all local or streamed from a sever with smb. Braveheart was all local.

I also have 1GB switches just in case.

I can confirm the exact same issue of the "slowmo" experience. Posted my debug logs as well in another topic about this here.

The problem occurs to me on two pc's, both with more than adequate specs from local disks as well as a full gigabit cat 6 cabled network.

I get a lot of these in my logs;

560.17:46:05 T:2928913264 M:1888010240 DEBUG: CPullupCorrection: pattern lost
561.17:46:07 T:2928913264 M:1887883264 DEBUG: CPullupCorrection: detected pattern of length 24: 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00
562.17:46:58 T:2928913264 M:1888272384 DEBUG: CPullupCorrection: pattern lost
563.17:47:00 T:2928913264 M:1888272384 DEBUG: CPullupCorrection: detected pattern of length 24: 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00
564.17:47:50 T:2928913264 M:1888407552 DEBUG: CPullupCorrection: pattern lost
565.17:47:52 T:2928913264 M:1888440320 DEBUG: CPullupCorrection: detected pattern of length 24: 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00 41000.00 42000.00 42000.00 42000.00 41000.00 42000.00 42000.00

Don't know what they mean but they seem to be connected to the "slomo" effect I'm experiencing.

It happens on both the XBMCBuntu install on a ubuntu 10.04.01 LTS Server as well as an install of the XBMC 10 Live cd (or running the live cd on it's own)

Hopefully the cause of this will be found soon because it's driving me nuts.
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#15
Same here - in each of these slowmo-stutters xbmc drops 5 to 7 frames here... but i can't see anything in the log...
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Slight Judder with VDPAU0